Conventionally, fiber structures, such as a fabric, a mat (flocked fiber material), and a fiber reinforcing material, are used for the purpose of heat insulation, sound isolation, and other purposes in ordinary houses, and various establishments, such as hospitals, schools, and accommodations, and various transportation means (vehicles), such as cars, airplanes, and vessels. In another side, the components containing these fibers or fiber materials are desired to be formed from a fire retardant material.
Polyetherimide has excellent fire retardancy, and is known as a useful material as a fabric required for fire retardancy, or a material for a fiber reinforcing member. For example, Patent Document 1 (WO 2010/109962) describes a polyetherimide-based fiber having a shrinkage percentage under dry heat at 200° C. of 5% or less, and a heat resistant fabric containing the fibers. Patent Document 2 (JP Laid-open Patent Publication No. 2012-41644) describes a nonwoven fabric containing amorphous polyetherimide-based fibers and a molded structure formed by heating the nonwoven fabric to make all or a part of amorphous polyetherimide-based fibers to be fused. In Patent Documents 1 and 2, carbon black is described as one of the choices of the inorganic substances which may be contained in the amorphous polyetherimide-based fiber.